Impulse counting relay and system therefor



Sept. 9, 1952 T. P. FARKAS 2,610,242

IMPULSE COUNTING RELAY AND SYSTEM THEREFOR Filed March 20, 1948 4Sheets-Sheet 1 FIG.

m far/6'4 F/G6 INVENTOR I P. FAR/(A 5 Sept. 9, 1952 T. P. FARKAS2,610,242

IMPULSE COUNTING RELAY AND SYSTEM THEREFOR Filed March 20, 1948 4Sheets-Sheet 2 FIG. 7

lNl/EN TOR 7. P. FA RKA S A T TORNEY Sept. 9, 1952 T. P. FARKAS2,610,242

IMPULSE COUNTING RELAY AND SYSTEM THEREFOR Filed March 20, 1948 4Sheets-Sheet 3 L INE lNl/ENTOR 7. P. FA RKAS Sept. 9, 1952 T. P. FARKAS2,610,242

IMPULSE COUNTING RELAY AND SYSTEM THEREFOR Filed March 20, 1948 4Sheets-Sheet 4 FIG. 9 I22 F/G. /0 20 w 1 F0 m m "0 FIG. F IG. /2

OIFFEREN TIAL lNl/ENTOR T. R F ARK/15 ayj A TTORNEV Patented Sept. 9,1952 IMPULSE COUNTING RELAY AND SYSTEM THEREFOR Thoma P. Farkas, JacksonHeights, N. Y., as-

signor to Bell Telephone Laboratories, Incorporated, New York, N. Y., acorporation of New York AppL cation March 20, 1948, Serial No. 16,091

11 Claims. 1

This invention relates to electrical impulse signaling systems and moreparticularly to improvements in magnetic counting relays and circuitsfor selective calling of telephone or teleraph stations of the typedisclosed by C. N. Hickman in ccpending application Serial 758,904 filedJuly 3, 1947 now Patent No. 2,589,806.

An object of this invention is to provide an electrical-impulse countingsystem responsive to a continuous train of electrical impulses received.in uninterrupted sequence.

Another object of the invention is to eliminate the requirement for aslow-release characteristic in magnetic contact counting relaysheretofore employed in a telephone station calling system.

Another object of the invention is to provide an improved magneticcontact relay structure wherein the tendency of such contacts to stickis overcome and wherein a positive break of successive contacts isassured for each impulse cycle.

A further object of the invention is to reduce the space required forselective signaling apparatus of the magnetic contact relay type.

A still further object of this invention is to provide a simplifiedelectrical impulse counting circuit wherein a magnetic contact countingrelay is operable directly by such conventional means as a standardtelephone dial, without the necessity of an intervening pulsing relay.

In the use of magnetic contact counting relays of the type disclosed byG. R. Stibitz in Patent 2,305,450, issued December 15, 1942, forselective signaling purposes, it has been found that the magneticcontacts sometimes display a tendency to stick when they should open,and this tendency has reduced the speed at which such relays could beoperated and even, in some cases, has caused faulty or incorrectoperation. This tendency for magnetic contacts to stick has beenattributed to residual magnetism remaining in the contact members afterdeenergization of the operating coil, and in part to leakage fluxthrough magnetic members of one side of the structure from theenergizing coil associated with members of the opposite side of therelay structure. Heretofore, the effects of residual magnetism andleakage flux which cause this tendency for contacts to stick have beenovercome solely by the application of a more powerful magnetic field tooperate the relay against these restraining forces. It is apparent thatthis solution to the problem has required more power for the operationof the relay than would otherwise have been necessary. In the presentinvention an additional element has been introduced into the relaywhereby the effects of these undesirable forces are overcome and therelay is rendered operable by less power.

Another difiiculty encountered in the use of magnetic contact countingrelays for a selective signaling system is the necessity of providing aslow release characteristic for one side of such a relay when used fordigit counting, as disclosed by the copending application of C. N.Hickman, Serial No. 758,904 filed July 3, 1947, now Patent No.2,589,806. Because of the inherent fast operate characteristic of theserelays, and because of the relatively low current required for theiroperation, and the comparatively weak magnetic fields which are set up,as compared with other types of relays, it is more diflicult to providea slow release characteristic for relays of the magnetic contactcounting variety than it is for other types. To overcome this difficultythe inventor has devised a new and improved electrical impulse signalingcircuit in which magnetic contact counting relays Without any slowrelease characteristic are employed.

In all similar systems for signaling or impulse counting, heretoforedisclosed in the art, it has been necessary to employ two relayarmatures to count each individual electrical impulse, i. e., onearmature would operate at the beginning of each impulse and a secondarmature would operate at the end of each impulse. Although thisarrangement is quite satisfactory for systems employing a short train ofimpulses for each digit or group, it becomes apparent that if largergroups of impulses are required, as may be the case in many signalingapplications, the size of the necessary relay stack with two armaturesper pulse may become unwieldy, or even so large as to be inoperable.Therefore, the inventor has devised an improved impulse counting circuitwherein only one armature of the counting relay is operated by eachcomplete pulsing cycle. With this arrangement the over-all height of arelay stack as may be required for any particular impulse countingoperation may be reduced to approximately one-half that formerlyrequired. With this reduction in over-all size and its attendantreduction in space requirements and cost of apparatus, there is alsogained a greater concentration of magnetic field which results in moreefiicient operation of the relay, less operating current being requiredthan in the case of the larger structures.

I-Ieretofore, all impulse counting circuits employing magnetic contactcounting relays have included a continuity transfer pulsing relay,responsive to dial pulses, by means of which the operating coils of themagnetic contact relay are alternately energized and deenergized. Theinventor has discovered that by a rearrangement of the operating coilson the impulse counting relay, the need for a pulsing transfer relay maybe eliminated. Thus, in some applications, an additional economy ofspace and apparatus may be enjoyed by this means.

Still another former limitation of the magnetic contact counting relayshas been overcome by the present invention. Th-is ,;1imitation was theimpossibility of recycling former types of such relays. This limitationhas been overcome in the present invention by the addition of an extraarmature tongue at one end of he,.cqunting relay stack. By this means,herein 'discloseda V magnetic contact counting relay may beautomatically recycled so that-it willprespond -continuously to anuninterrupted=train ofiimpulses for an unlimited time. With= such anarrange merit the inventors improved magnetic contact counting relay maybe used :in: any lja l plication where continuous stepping switches haveformerly been employed. Thus the utility-ofthis type of relay may now beextended to many additional operations in systems.

The n re andioneration inf-l the p ese vention may be more; clearlyunderstood from a consideration or thedetailed description which fowsrwh n studied. in-connectionv with-the -rea e dra ngs wher gl igal isan explodedand; pa tlycutaway isome icd awi e showi g. the; essentialoperat n elements of a magnetic .contact;counting relay of th yp mbod edin-the present invention;

- Fi 21 a, ners e tiv drairin ofta singlearmatureilamination otthetypemplcycdinzthe first, third and-fi t layers .ofvtherr lay stacks illus aedla 1;

Fi 3 i p sp ctireedrawineoilapill learmature lam n t on; of the typecmployedinthe secnd, ur h and 3 XQ I$i;:Qf: lhQ. I21a5/"fiiiacksillustrated by Fig. 1;

1 F 4 is a .topp am wioi .thearela-y stacks of Fig. 1 showingtherelationship between'operating coils, pole-piecesandahmaliures;

Fig. 5 1s a front viewrelevation -of tithe relay stacks of Figs. 1- andi showing the, relationship between pole-pieces andarmatures;

Fies azschematic,dia ramicfarelay .of the type hereinmsclosedch min anaux li yannaturet n ue .lllat one end of the c ytstac nected with theoperating coil andassociated pulsing; relay; whereby theimpulse,countingrelay; may be recycled ,andthusenabled torrespondcontinuously toimpulsesas received in; seguence;

Fig. -7 is a schematic. d ia-gram oftwo: impulse counting relaysof-the,typephereinidisclo edt interconnected to jcomprise ,a completedigitalase lective signaling system, In.,thi figure-may-be seenv anadditional: armature tongue L5!) .in. the digit counting relay stack.wherebyoperating coils of this relay ,are held energizedduringiitheeinterval between transmission of; successive digits, therebyeliminating the-need. .ior aslow. release characteristic to be built,into the relay .istructure. Tols plifylt e app ara e of Fi Landreducethe possibility o circuit confusion, the insulated tu whi h ext nd btween armature tonguesare not illustrated in this drawing. ,fIfongue..50, unlike all the other tongues,..has :no insulated s udassociatediwith it;

Fig. sis aschematic diagram showin themaner in wh ch a ,maene ic,contaot. counti erelay, of the type embodied in the present invention mabe. inte connected with two pulsing r aysso t at on armature ton ue of.the. counting relay will come ,up for :each complete pulsin yc .In th s.arrangement,- as illustrated, a re.- ay ,stackihavi e only. ten armaturetongue may be employed to, count asimanyas ten impulses, whereas: in allarrangements, ,preyiously-disclosed such a relay structurewouldheliniitedto counting .awmaximum of.... n.ly nveinipnlses.

te ephone "plants -.-and

s tongue Ill, have associated insulated studs as shown by. Ei s. l6;

ZJ; Fig.; 9,.is a schematic diagram showing one arrangement in which amagnetic contact counting relayofthertype embodied in the present inven-11'0" -tion maybeoperated directly-from dial pulses, without theinterconnection of a pulsing relayas previously required in all suchimpulse counting Fig. 10 is a top plan view of a relay stack of thetyperepresented schematically in Fig. 9, showing one operating coilpositioned around the center armatures, ;an.d:the ;other ,;operatingvcoil around the pole-piece leg :of-one. side of. therelay structure;

- 1Fig.1lristaschematiddiagram of an alternative circuitby lneansofwhich a magnetic counting relay.oLthe-type-embodied. in the presentinvention-may; be ;operated:directly: from dial impulses; ;'Fig.;121 isatop plan-view of .a relay stack of the ynezrepresented;schematically byFig. 11, here showing ztheiocationaof a differentially wound operatingcoil on one legof. the relay pole-piece arms. I 1;Iihezgencralprinciples involved, 'and'the method ofroperationin magnetic contactcounting-rel yszforrin pulse counting, and signalin are describedcopendin zapplication; of C. N. Hickman.:aSerial.-,No: 753,904,;andbyxreference thereto thecdisclosureand drawings of :said applicationarezherebygincorporated into the specification ofheiprescntapplication.i In .the stepping relays previously disclosed,the :advantage of magnetic contacts,rwhichrprovide a high contactpressure for a relativelylow-operating current, were oifset toaklargeidegreebythe disadvantage of residual magnetismand-leakagefiuxwhich tended to hold the-backz-contactsi closed at atime when theyshould be; Opening .for' the stepping operation. Herctofore .theproblemhas been to provide a relay with sumcient contact pressurebetween the pole-pieces and .back contacts of the armature to-satisfysthe requirement of noise-free telephone circuits: and at thesame timeassure positive st pping operation of: the relay on each energizingcycle. :of- :the ;operating coil. One possible solution-to -the;;pr0b1emof residual magnetism andcleakagev flux is the substitution ofnon-magneticdiscs for-themagnetic back contacts as disclosed in theprion-art. However,. this solution limits the use of the stepping relayto those applications. where back :contacts are not required inthecircuit.

, :In the; present inven-tion the problems discussed above are,solvedbythe addition of an auxiliary branchleg H l in Fig. .2, -tothearmature laminationsin alternate layers of the relay stack. Auxiliarybranch-Elli may=also be seen in Fig. 4, and auxiliary branches l.l,"l3and l5rmay be clearly seen Fig.5. sEachof. these auxiliary branchescarries :a magnetic contact on the lower face of v,its,,-forwar.dextremity, which engages a correspondingmagnetic contact-on the upperface of th vleft-hand.pole-piece to which the auxiliary leg is adjacent..In the entire .relay structure, when ,.comp-le.tely assembled, theseauxiliary branch legs .maymormally be biased downwardlybythespringtension of the leg itself, although such, springitension,islnot essential inasmuch as an ample contact pressure may beassuredbythe passage ofmagneticiiux through this auxiliary branch memberandits. associatedmagnetic con-V tacts with the adjacent magneticpole-piece. By reference to Fig. 5, it will be observed that the mainarmature tongues in each layer of the relay stacks, as represented by I,2, 3, 4, 5, and 6 in this view, all carry magnetic contacts on the upperfaces of their forward extremities in a position to engage correspondingmagnetic contacts on the lower faces of the pole-pieces adjacent to andnext above each of the main armature. tongues. However, these armaturetongues differ from these previously disclosed in that they are providedwith non-magnetic spacers on the underfaces of their forwardextremities. These main armature tongues are normally biased in adownward direction sothat even when the relay is completely deenergized,the non-magnetic spacers are held against the pole piece below thearmature tongue by means of the spring tension in the tongue. The highreluctance introduced into the magnetic circuit between each 4 of themain armature tongues and the magnetic pole-piece immediately below bymeans of the non-magnetic spacers eliminates the undesirable effects ofresidual. magnetism and leakage flux as heretofore encountered. Thus themain armatures are freed from the retarding magnetic ini'iuencesformerly exerted through magnetic back contacts and thereby are enabledto come up quickly in succession in response to pulsations of theoperating coils.

As in previous magnetic stepping relays, sue cessive operation of thearmature tongues is assured by non-magnetic insulating studs which areinterposed between armatures in adjacent layers of the relay stack andby means of which all armatures except one are disabled from operatingat any time, and operation of the one free armature lifts a restrainingstud from the next adjacent armature thereby enabling it to operate onthe next pulsing cycle. Referring now to Figs. 1, 3, i and 5, theinsulating studs may be seen at ii, iii, I3, 23, 2! and 22. It will beseen that insulating studs are provided for each auxiliary branch leg,as by H, I5 and 2i in Fig. 5, and that these studs are separate fromthose provided for the main armature tongues as shown by I8, 29 and 22in Fig. 5. The studs affixed to the auxil iary branch arms are somewhatshorter than the corresponding portion of insulating studs which arefixed to the main armatures. Although this slight difference in lengthof studs is not clearly apparent in Fig. 5 because the ends, of eachstud are hidden from view behind magnetic contacts on the armatures, thespacing referred to is clearly illustrated by Figs. 9 and 11 wherein thestuds are not drawn in their true lineal relationship but are shown outfrom behind the concealing magnetic contacts. Thus it is that the studit which is affixed to auxiliary branch leg I I in Fig. 5 has a gapbetween its lower extremity and the upper face of main armature 2, whichgap may be of the order of ten one thousandths of an inch to providelost motion coupling between the adjacent main armature 2 and auxiliaryarmature I I. Similarly the stud I9 which is afiixed to auxiliary branchleg I3 has a corresponding gap between its lower extremity and the uppersurface of main armature 4, and in like manner stud ZI ailixed toauxiliary branch leg 25 has a gap between its lower end and the top faceof main armature 6. The gaps thus provided aid in opening the magneticcontacts of the auxiliary branch leg against the forces of residualmagnetism and leakage flux through the auxiliary branch. The manner inwhich these forces are overcome may be better understood from a detailedanalysis of the operation of this relay.

Referring now to Fig. 5, we shall trace in detail the process ofoperation involved in this relay. If we start by energizing left coil LCit is apparent that the first armature tongue I will be attracted upwardinto magnetic contact with upper lefthand pole-piece 3I. At the sametime, auxiliary branch leg II is held down by the magnetic attraction ofleft-hand pole-piece 33, and armature 2 is similarly held down by thecombined forces of its spring tension bias and the magnetic flux flowingthrough left-hand pole-piece 35. The third armature tongue 3 is alsoattracted by the magnetic field of left-hand pole-piece 35 but thisarmature is prevented from rising by the downward force exerted fromarmature 2 through its protruding insulating stud I8, the force betweenarmature 2 and pole-piece 35 being much greater, than the force exertedby pole 35 on armature 3 because of the difference in spacing. In likemanner, armature 5 is restrained from moving upward by the downwardforce of insulating stud 20 protruding from armature 4 which in turn isheld down by the magnetic pull of lefthand pole piece 39. In thisinitial condition with only the left coil LC energized, all of theauxiliary branch legs are held in magnetic contact with their adjacentleft-hand pole-pieces. Now if the right coil RC is energized, all of themain tongues except one will be attracted downwardly so that no movementoccurs. The first tongue I which is already up now experiences a pullagainst upper right-hand ole-piece 32 whereby armature I is held in itsupward position. Now if left coil LC is deenergized, the second tongue 2is no longer held down by a magnetic pull from polepiece 35 but isinstead attracted upward by the magnetic pull of right-hand pole-piece34. At the same time, contact between auxiliary branch leg I I andpole-piece 33 is opened by action of the insulated stud I! which isstruck by armature tongue 2 in its upward traverse. At this time,armature tongue 4 is attracted upward through the magnetic pull ofright-hand polepiece 38 but is prevented from coming up by therestraining force of stud 20 afiixed to armature tongue 3 which is helddownward by the greater magnetic pull of right-hand pole-piece 38. As wehave seen before all main tongues below are similarly restrained by theinterposed insulating studs. N ow if the left coil LC is againenergized, all armature tongues which are up will remain up, while allarmatures which are down remain down. If the right coil RC is nowdeenergized, tongues I and 2 which are already up will be held up bymagnetic contact with polepieces 3| and 33 respectively. Armature 3having been enabled to move by the previous lifting of insulated stud I8now comes up into contact with pole-pieces 35 and 36, being held in thisposition by the magnetic attraction of pole-piece 35. The auxiliarybranch I3 remains in intimate magnetic contact with pole-piece 31, and acircuit is now closed between pole-pieces 35 and 31. As we have seenpreviously, none of the remaining armature tongues comes up. However,when RC is once again energized and LC subsequently deenergized, thefourth armature tongue 4 will then rise under the magnetic attractionexerted by right-hand pole-piece 38, and in coming up armature 4 strikesinsulated stud I9 thereby opening the magnetic contact between auxiliarybranch I3 and pole-piece 31. In like manner, upon successiveenergization and deenergizationoi'the leftandright coils alternately,the remaining armaturetongues inthe relaystackwill step, upsuocessively..Thus it is readily. seenthat. in. each complete pulsing cycle,onecircuit betweenadjacent .lpairs of .leftrhand pole pieces is'closedand ajprevious -.su,ch. .circuit issopencd Thisstepping operationmay bacontinued. for as. many. impulses as there are-pairs of armaturetongues in the. relay. stack.

... In..reerence to .Eig. 5..itmwillibeiobseryed that although. backmanetic contactshaveheeneliminated iromthe underside oithe. .main armaturetongues, ,the -non-magnetic spacingprovided between. these -membersnand..the 1 POIGrPiECBS. .adiacent to. theirnndersideislmuch less than .thenormal air-flap. .betwcen :the i ppermagnetic contactsof thearmature.tongues'and the next pole-pieces adjacent .above .the armature. It isbyv means of. these -non.-.ma netic .back spacers that .theundesirableeffects. of residuahmagnetism and leakage fluxgwhich in previous relayshave. .occasioned. unreliable operation clue to armatures sticking whenthey. :should have stepped. are eliminated -inthe present invention. It.will .beobseryed. that. in the. idle. relay conditionas illustratedby.Fi,g. '5, armature .l,i isiin closerproximity to rightehandpole-piece .34 than it is. to-.eith.e,r of .the.,upper pole-pieces Blandas. It will be, apparentthat if the right coil-RC isiirst. energized,armature I will be subjected to a. magnetieforce irom upper right-handpolepie.ce...32, but that dueto. the greaterair-gap between these .twomembers as. compared with thespacing. between. armature I. andright-hand 130161131606 34, the. armature, will not be attracted upwardbut. instead will remainnin its lower po-.

sition held there under .the combined influence of. its downward. springtension :and the downward magnetic .forceexerted by the attraction ofpole-piece .33..v .It is .only whenthe left coil LC is..energized andthe right coil .RC ,deenergized, that. armature I yields to the upwardattraction otmagnetic .iorce from upper .left-hand-polepieceBl as wasseenl in thedetailed analysis of the relay operation. :Siniilarly whenonlyleft coil LC is energized, armaturel now. being up in intimate.magnetic contact with pole-piece 3i, armature ,2 issublected to aslightlifting. force due :to themagnetic. attractionof left-hand polepiece..33but.....this force is. much. less,,than the downward pull oflef.t-,l1and -pole-piece 35, so thatarmature .Zi-Jemains .down until the.next cycleof pulsing.whereuponright coil-RC is energizedand left .coil.LC. .deenergized at. which time armature .2 .ccmesup. under themagnetic. in fluence. of. upper -right1hand pole-piece-.3,4. Inlikemanner .the spacing and spring :tension- :bias of..all remainingarmatures issuch that they remain in. their .downward position until-they are first .enabledto come .up by the lifting .of :an insulatedrestraining 'studand then are brought up .by the magnetic attractionofan opposite upper pole-piece.. v.Inthepresent invention-therefore, notonly are vthe.rundesirable eflects of residual vmagnetismand leakageflux eliminated fromlthemainiarmature tongues-by means ofnonrmagnetioback.spacers, .but the contact to be brokenon eachsuccessive stepping operation has been transferred to anauxiliary armwherein positive contactrlosure isassured through the intimate adhesionof magne.tic..contacts, yet the positiveiinterruntion of .this contactis also assured, when desired, .through the. action .of-the nextsucceeding .main armature, on an insulated stud attachedto.th,e...-.auxi1iary.arm. By means oi:.the....s.1ight vgannro.videdbetween the auxiliary arm.s.insulated.stud andthe next adjacent largearmature which,operates-,upon-it,the main armature on every, operationis allowed to start its upward traverseand by means of this lost motioncoupling thus acquires sufficient kinetic energy to alwaysinsure openingthe, auxiliary contact upon strikingthe insulated stud. The undesirableefiects .ofresidual magnetism and leakage flux in the present inventionare minimized in the contacts to be broken by ,virtue of the thinmagnetic member, which .carries this contact, and the .resultingincrease ,inreluctance through this portion .ofthe ma netiocircuit. Thesmallsize of .the auxiliary branch arm also-reduces the springtension tobe overcome in breaking this magnetic contact, thereby furtherfacilitating the. positiyeinterruption of this circuit as the relaystepsin response tosequential impulses. Inasmuch as the auxiliary branch armmay be stamped .irom the lamination which carries th main armature togueas illustrated by fi -1 noadditional operation is required to formthis member and no added cost is thereby incurred. Although theauxiliarybranch armature could be formed. of asep r niececf metal withoutdeparting from the spirit or principle of the present inventionanotheradvantage of the arrangement illustrated by Fig. 2 isthat'internalstrapping between the make contact and the break contact members iseliminated, thereby reducing materially the cost of assembly and wiringof such stepping relays. Another advantage aiTorded by the relay of thepresent inventionis thatindependentuandisolated circuits may besuccessfully controlled by the device herein disclosed, whereas allpreviously disclosed magnetic stepping relays were limited to theoperation of connecting anyone of a given number of lines to acommonline nnlessanother pole face piece wasadded for. each pulse as inthe Stibitz patent. As wasseen .in the detailed analysis of the relayoperation in reference to Fig. 5, a circuit isfirst closed betweenpole-pieces 3| and 33, then on the next pulsing cycle this circuit isopenedand another circuit is closed between. pole-pieces 35 and 31. Inlike manner the next impulse cycle opens the circuit previouslycompleted between pole-piecestli and 37 and then closes another circuitbetween pole-pieces 39 and Al. 'Thus it may .be seen that a plurality ofisolated circuits, each. separate andinsulated from the other, may becontrolledby the stepping relay of the present invention.

, ,Eteferringnow to Fig. 6, we see a schematic circuit diagram inwhichthe stepping relay ,of the present invention is-connected in amanner torecycle, or in otherwords continuously respond to sequential electricalimpulses as received, without limit to the inumber of such impulseswhich may .be received. Here it will be observed that the circuit foroperating the left coil LCis completed through the last contactsin the,relay stack, Ill, in such, manner that when aseries of vimpulses hasbeen received which operatesall of the armature ton ues in sequencetoandrincluding the last, armature tongue, the automatic opening of thecontacts 1.0; in responseto the tenth impulse received-will open thebattery circuit through left coil .LC' thereby allowingall armatures ofthe relay'stack to fall oiT intotheir normal .position as biaseddownward when the both coils of, the relay are deenergizedr :This thenautomatically resets the relay, thus conditioning it tostartStEPping-irom the topall over spond to successive impulses asbefore.

again in response to the next or eleventh impulse which may be receivedin sequence without interruption. The recycling contact IE1 may becarried on one of the auxiliary branch arms, in which case it is openedindirectly by operation upon an insulated stud, or it may be of the typeillustrated in Fig. 6 which is opened directly by movement of themagnetic armature tongue. We will nowtrace the sequence of operation inthe circuit of Fig. 6. Pulsing relay PR is operated by electricalimpulses received from battery M in the circuit controlled by operatorsdial [2, or this pulsing relay may be operated by any sequential seriesof electrical impulses as employed in telephone signaling. Operation ofthe stepping relay is identical with that described in reference to Fig.until we come to the last armature tongue l0. Here on the operation ofpulsing relay PR for the ninth time, contact 1 closes completing acircuit from battery 16 through contacts ID to energize the left coilLC. Subsequently contact 8 opens, thereby deenergizing coil RC andallowing the next to the last tongue 9 to come up. A circuit is nowclosed through the ninth pair of pole-pieces on the left side, and allother such circuits are opened. On the release of pulsing relay PRcontact ti closes, coil RC is energized, and contact I is opened,thereby deenergizing left coil LC and allowing the last armature tongueI0 to come up. The auxiliary branch arm of the previous tongue is openedby operation of armature ID upon the insulated stud associated with thisauxiliary branch, and circuit 9 between the lefthand pole-pieces of therelay stack is thereby opened. Contact ID connected in series with leftcoil LC is also opened by this operation. Now upon operation of pulsingrelay PR. for the tenth time, contact 1 closes but coil LC cannot now beenergized since contact Ill is opened. Then when contact 8 of pulsingrelay PR subsequently opens right coil RC is deenergized, thus creatinga condition in which both operating coils of the stepping relay aredeenergized and all of the armature tongues of the relay stack fall offinto their normally idle positions. But, in returning to its normaldownward biased position the last armature again-closes contact 10thereby energizing left coil LC through contact I of the pulsing relayPR which is still operated. This energization of coil LC now brings upthe first armature tongue and closes a circuit between the first pair ofleft-hand pole-pieces, O. The stepping relay has now started its secondcycle and succeeding armature tongues will re- This recycling feature isconsidered highly desirable in many applications within thecommunication industry. Of course, it is to be understood that thisrecycling arrangement is not limited to a stepping relay having tenexternal control circuits as illustrated in Fig. 6, but may be employedwith any size of stepping relay having either more or less than tencontrol circuits.

Referring now to Fig. 7 we see a schematic circuit diagram of a completeselective signaling system employing two magnetic contact countingrelays of the typ v comprehended in the present invention. A significantadvantage which this circuit offers over all previous circuits fordigital signaling systems employing magnetic contact stepping relaysisthe elimination of the former requirement for-a slow releasecharacteristic in the digit'counting relay. Experience i ha's'indicatedthat because of the inherent fast 10 operate characteristic of relays ofthis type it is quite diflicult to build a satisfactory magneticcounting relay of sizeable proportions with an adequate slow releasefeature.

In the circuit of Fig. 7 the slow release sleeve formerly required on.one operating coil of the digit counting relay has been replaced by anauxiliary armature tongue 50 which engages an additional magneticpole-piece 5i whenever the left coil LC of digit counting relay DCR isenergized, thereby providing a positive means for locking up this sideof the relay during th interval of pause between digits. The manner inwhich this functions will be better understood from a study of thedetailed circuit analysis following.

Another advantage which thearrangement of Fig. 7 offers over allprevious circuits for selective signaling by means of magnetic contactstepping relays is in the elimination of chains of series contactsthrough the magnetic contact members of the relays. As described inreference to Fig. 5, the auxiliary armature legs afford a means forcontrolling a plurality of separate isolated and insulated circuits insuccession without the necessity of carrying the control circuitsthrough more than one pair of magnetic contacts, as heretofore wasrequired in all previous circuits. By thus reducing the number ofcontacts in series, the relay device of the present invention reducesthe probability of circuit failure due to noisy or open contactconditions developing between the magnetic contacts. Still anotherimprovement offered by the arrangement of Fig. 7 is a reduction in theover-all power drain required for operation of this selective signalingsystem. The manner in which these advantages are obtained will be moreapparent from a detailed analysis of the sequence of operation involvedwhen considered in reference to Fig. 7.

In general, the operation of this circuit is similar to that of thecircuit disclosed in the Hickman application previously referred to. Inthe latter circuit, if the pulse counting relay is energized the correctnumber of times an alternate path is established through th contacts ofthe pulse counting relay and the digit counting relay in such a mannerthat the left coil of the digit counting relay holds up when the slowrelease relay falls off during the brief pause at the end of each digit.Since this holding circuit passes through the contacts of the pulsecounting relay, it is necessary also to hold up one of the coils, asshown, the right coil, of this pulse counting relay. Then at the startof the next digit, it is necessary to release the pulse counting relayso that it may return to its initial idle position, and this release isaccomplished by momentarily opening the holding circuit. Consequently,the left coil of the digit counting relay in that circuit is alsoopened, and the armatures which have already counted digits will falloff unless a slow release characteristic has been built into this coilof the digit counting relay. Because of the inherent fast operation ofrelays of this type, it has been found difficult to design suitablerelays having a sufficient slow release holdup characteristic. However,in the present invention, by means of the arrangement illustrated inFig. 7, this problem is solved through .the operation of the auxiliaryarmature 50 in cooperation with this contacting pole-piece El. Thesequence of operation in the circuit of Fig. 7 when the pulsing of adigit is completed and the slow release relay SRR falls off is asfollowsz'First, assuming r that the "correct "number *ofimpulseshad'been -*'received, the leftcoil LG-of =digit counting relay-DGRrwill'beenergized through one pair of contacts on the digitcountingrelay andanother pair cf-contacts on the-pulsecounting relay.Simul- -"'taneouslyfithe' armature 50 comes up into intimate'magneticicontact with the-adjacent "polepiece 5l to-provide analternate'path for current -through*left coil 13C; thereby'locking;upthe 'relay DER.- "Next the completerelease-cf the slowrel'e'asei'elay -SRR--opens'-'the battery circuit to the -'operating=-'coil of the pulse-counting relay PRi thereby restoring thatrelay-toits normal idle pcsition. Since the pulse counting relay is thusrestcred'to normal at the end of each-digit, there is no power drainholding up thisrelay during the-in'terVal-"betweendigits; and no need"-to rstore this relay *to -normal 'atthe' start of the next succe'edingdigit,-a's has heretofore been -required. Thus it" is l clear that withthe circuit -"of 'Eig-, 'Yth" left coil of-the ni h-" relay =cannow'be-'deenergized 'after the right coil is energized at the start ofthe-succeeding" digit, sc -that there' "is no need'for a}slow-'releasefeature to beincorporated intheleft coil of this delay.*Since' -"only the coil on "the digit counting --relayis here'en'e'rgizecl- -at the end of a correct digityandthere is =no energizing"of theleft coil on th digitcount-ing-relayduring'the pulsing of a'di'gitas previously;- the powefdrain required by *this circuit isconsiderably" less than that required byall"-previous selectivesignaling systems employing" magnetic contact stepping relays. 'Theaddition "cf the resistancROinseries with thhdldingcirduitbf digitcounting relay 'DCR '-operates to reduce "the current-through "the left*coilLCto a=minimum hold valuei thereby further reducing thepower drain.I

i For a betterfimderstandingof the operation of the-selectivesignalingsystem "illustrated by mg; 7;we Will-nowtracetheseque'ncebf operation 'step-by-step. Upon operation of theoperators dial -59;-which=may be located at a'remote central oifice-,with theswitchhook 58-closed as illustrated, a series'= (if-"electricalimpulses are transmitted from battery 60' through" loop- 51 to pulsingrelay PRf When the pulsing relay" 'PR is energized by the first receivedelectrical impulse, contact 6! closes,-"-contact 63opens; and-contact-62 closes to -"-complete a ci-rcui t frombattery fifi'through slowrelease relay' SRRf Upon "operation 'of SRR, contact- 65 closes-thereupon"*energizing the righthand coils of digit counting-relay -DCR;and pulse counting r'elay *PGR," respectively. "Now in re- 'sponse tothe' magnetic attraction of the upper right-hand pole-pieces inbothstepping relays, the firsttongu't'l; of-PCR and 68 of DCR come up.Gontact 64 of slow -release' relay SRR, opens "-but no 'a'ctionnow-occurs'as the circuit through armature-'50andspole-piece 5| of digitcounting relay DCR is open. "Now at the 'end of the 'first 'impulse,pulsing'relay' PR is'deenergized; contact 62 opens and deenergizes slowrelease relay SRR, butthis-relay-does-not open due to'its-slow're-"-lease 'characteristic. Contact 63 closes thereby energizing left-'coil LC of pulse counting relay PCR. Contact 6| opens;thereby-deenergizing r htcoil R of pulse counting relay PCR' andallowing the second armature tongue 69 *of "the "pulse counting relayitocome upunder the'mag- 'netic attraction ofv the left-hand poleepiecelll.

' At'thestartof the second impulse, pulsing relay 7 'PR- is-again'energized; contact 6| again eloses to energize coiIRCHof pulse countingrelay PCR, contact '63now opens, thereby deenergizing coil 12 LCof pulsecounting relay P'CR and a'll'owingithe third-"armature" tcngue- 'H'es-Pea kto 'comey-up. Contact 62- closes; completing the operatingcir--cuitthrough slow release relay SER,*-but-'no turther operation :or thisrelayl n'ow occurs because 'SRR-had not previously released due to itsslow release characteristic. "Whe'rr-"the pulsingrelay ER; is-deenergized='at?the end of thes'econd'fimpulseglcontact R opens theieby deenergizingfislow i to its slow-release characteristic;=contacir-B3clcses thereby energizing e011 LG-of pulsecouiitmg re- -lay PCR, andcontact fil opens thereby deen'e'rgiz- 'ingcoib RC and allowing" thri-fourth armature 15 tongue -13 of PCR 'to COMe'fupJ "Ihus lt-"is" seenthat for every completeipuls' I systerm two armaturetongu'es-bf thepulseeounting relay -cjome' up. Y On -the last impulse-received in atrain; the: interval between digits is' 's'ufiig :-cient to allow theslow release relay SRR, to fall off, and at' 'this 'time there are two:possiblee-occurrences, dependingonri wliether' thefinuinber which:was-dialedis'correct or-' not.

If an incorreetnumbenhas been dialed; the -following sequence iresults.TVVhen the slow release relay SRR; finally falls ofi contact 64; closes:but coilLC' of digit'coun'tingrelayDCEcamiotthereby be-energized' smcethere is no path establ-ished 1 through' the: contacts Jof the pu-lse:counting relay 9 and 'the digit: counting relayi Contact-2 65* opensand deenergi'zes. :co'ils RC-bf 'DERI and of i therebyallowingialllarmature tonguesiiofiiiboth :stepping relays to fall bfif flfhusiit is s'een that reception Jot: an incorrect digit 'operates'-toireset the! entire selectivesignaling circuittciits normal ,iidlecondition. v

I If,11hOWeVel,' lIhEZ CUI'IECtfCIig'itYhaS- bBGIf dialed, t thefollowing sequenceioccursii when slew release relay SRR? i-finallyirel'eases, ontactiifide Iclo'ses "thereby completing:- a" :circuitifrom: batteryiiififi nthrou'gh the fourth:armaturetonguafl aiofiepulse'7 counting-relay? PCRzwhicli -:has closed al' circuit rbetweenleft-:handapole-piecesil4:and 'IS of -PGR, thence through. the firstarmature:itongue fiaaof r'digiticounting relayttDCR; WhiChlh'BJScompleted a l 'icircuit betweenithe: rightehandmcl'e-pieces flfi andiground. ThussLOiis energizeiiathe:first armature tongueffiti'oflDcRsisheldiup', theeauxiliaryfcontact armature? i -.icloses."contact;mtnap'oleepiece 5'5 l i'thereby lockinggup zleft 10011?LcfoitajpR -andrthe second armatureiton'gue liii of EUR: is enabled:- to

operate. Contact i6 5: of \ES'RBKDPGDS, thereby deenergizing cone-RentDCR and IiG-b'f- PR thus allowing all the armature -tongues of the pulsecounting "relay to releaseand "at the same time bringing up thesecond-armature tongue |8**of correct digit-brings 'up' two armaturetongues 'of the digit counting relay and resets the pulse counting relayto normal. I

At the start 0f' the"neXt-=train: of impulses,

representing the second digity p'ulsing trela'y PR is energized onthefirst impulse; contact 6] closes,

a contact *63aop'ens7 and contact *62 closesf thereby "energizingslowfrelease relay -SRR. 'Contact"65 ofSRR,"closesthereby"energizingitheright-hand armaturetongui t 7 iof'PCRcomes ;up'. Contact '21E4 opens"th'eiiebyjdeenergizinglthileft.coil-LL6- of 1idigitlcountingvfelay' DOB-whereupon the-,l-th-irdarmature .to'ng'u'e 9 "or. 'DCR'. comesqup andlthe au'ii iliaryarmatureltongue 50.-;fal1s ioffi'd-isengagl ing contactl withpoleepiece"'5 I E The: circuit? is now in exactly the same condition asthat folrelease r'elay SRR-butyet? thisrelay-holds-up due l3 lowing thefirst impulse of the first series except for the fact thatnow the firstthree armature tongues of digit counting relay DCR are up instead ofjust the first tongue being up. Thus the path necessary through digitcounting relay DCR has now been changed and the correct number of pulsesrequired for the second digit may be either the same as or difierentfrom the number required for the first digit depending upon the mannerof interconnection between PCR and DCR. If four correct digits aredialed in sequence, all eight armature tongues of the digit countingrelay will come up, and a circuit will be closed between the fourtharmature tongue 83 and left-hand pole-piece 8| whereby the signalindicator 82 will be operated. The signal may then be interrupted by thesubscribers operation of switchhook 83. The operation of this switchhookcan also be used to clear the entire system. If the signal is notanswered, the entire system may be restored to normal by thetransmission of a single clearing pulse from the Central Office.

Referring now to Fig. 8 we see still another circuit employing amagnetic contact stepping relay of the type comprehended in the presentinvention. The subject matter of Fig. 8 is shown and claimed indivisional Patent 2,561,730. This circuit difiers from all previouspulse counting circuits employing magnetic stepping relays in that thecounting relay of Fig. 8 requires only one main armature tongue for eachcomplete pulse to be counted. That is to say, the ten armature tonguesin the relay stack of Fig. 8 will count ten impulses, one tongueresponding to each impulse as received, whereas as We have seen in thecircuits of Figs. 6 and '7, all previous arrangements of magneticstepping relays have required the operation of two armature tongues foreach complete pulse. An obvious advantage of the ar rangement of Fig. 8is the reduction of one-half of the number of armature tongues requiredto count any given number of impulses. A further advantage is that byoperating only one tongue per impulse, the circuit of Fig. 8 mayinherently require less time per pulse for counting, thus it is apparentthat with the arrangement. disclosed in Fig. 8 not only may the size andcost of a magnetic contact stepping relay be reduced but also the speedof operation may be increased.

In Fig. 8, as in Fig. 7, the insulated studs which extend betweenarmature tongues in adjacent layers or" the relay stack have beenomitted from the drawings for the sake of clarity and to avoid confusionin tracing the schematic circuit. However, it is to be understood thatinsulating studs of the type disclosed in Figs. 1, 2, 3, 4, 5 and 6 arealso incorporated in the magnetic stepping relay of Fig. 8; it is alsoto be understood that the left and right operating coils, designatedschematically as LC andRC respectively in Fig.

8, are wound around the laminated pole-pieces of the leftand right-handsides of the relay stack respectively, in a manner similar to thearrangement disclosed by the structure of Figs. 1 and a. The steppingrelay structure of Fig. 8 differs from those previously disclosed inthat it includes an auxiliary armature tongue I l l interposed betweenan auxiliary right-hand pole-piece H2 and left-hand pole-piece H3.Thisauxiliary armature and its associated pole-pieces may be placedeither at the bottom of the stepping relay stack as illustrated in Fig.8, or it may be placed at the top of :said stack, or it may be situatedanywhere else in the stepping relay amine structure, provided only thatit must not interfere with the stepping operation of the relay. Thefunction of this auxiliary armature tongue III is to indicate at alltimes which of the two operating coils, LC and RC, was the first to beenergized whenever both are operating. By reference to Fig. 8, itwill beseen that if the left coil LC is first energized, the auxiliary armaturetongue ill will be moved down into conductive engagement with left-handpole-piece 1 I3, thereby closing contact 9|. If the right coil RC isnext energized, tongue Ill will not move since the magnetic force due tothe closed contact 92 is much greater than the magnetic force throughthe open contact 92. However, if the left coil LC is then deenergized,armature tongue Hi will come up into intimate contact with righthandpole-piece H2 thereby closing contact 92. In this situation if the leftcoil LC is then re energized, the armature tongue 1 l I will not againmove until such time as right coil RC is deenergized. Thus it is seenthat armature HI always indicates which of the two coils LC and RC wasthe first to be energized. By means of the two contacts 9! and 9'2associated with the auxiliary armature Hi, the two pulsing relays PR!and PR2 are alternately operated on each successive impulse. Whenstarting from idle condition, operation of the correct pulsing relayinitially is assured by providing armature Hi with a slight pretensionin one direction, in the circuit illustrated by Fig. 8 this pretensionbeing downwardly, to insure that contact 9| is always closed when thecircuit is idle.

The detailed operation of the circuit of Fig. 8 will now be tracedthrough a step-by-step analysis. The circuit is first conditioned foroperation by closing a switch 89 which completes a circuit through coilsLC and RC and the battery 90. Armature tongue Ill remains in intimatecontact with left-hand pole-piece H3 toward which it was initiallybiased by spring tension. Now if the operators dial 88, which may belocated at a remote ofiice is operated, a circuit will be closed throughthe dial at the start of the first dial pulse, and-pulsing relay PRIwill now be energized through contact 9|. Upon operation of PR] contact93 first opens, then contact 95 closes to lock up PHI to battery 90, andthen contact 9'! opens, thereby deenergizing coil LC, Which in turncauses armature 10! to be .attracted upwardly into intimate contact withthe upper right-hand pole-piece. With LC now deenergized, auxiliaryarmature tongue HI is attracted upwardly into intimate contact withrighthand pole-piece H2 thereby closing contact 92. However, thisopening of contact 91 has no eiiect on pulsing relay PR! which as wehave just seen has already locked up through contact 95. At thisinstant, the closing of contact 92 has no eifect on pulsing relay PR2since contact 93 of PR! is open, thereby introducing a discontinuity inthe circuit through the operating coil of PR2. Now, at the end of thefirst dial pulse, the circuit through dial 88 'will open, whereuponpulsing relay PR! is deenergized, contact 91 closes and energizes coilLC, contact 95 opens, andcontact 93 closes, but pulsing relay PR2 cannotyet operate because the dial' contact 88 is still open. The energizingof LC at this moment has no effeet on the auxiliary armature tongue lHsince since current is already flowing through coil I28 of RC and thetwo coils are difierentially wound, the'magnetic fields oppose eachother and no flux will flow through the right-hand pole-piece members.However, when the contacts of dial I29 are opened no current will fiowthrough LC or through l2! of RC, so that the magnetic field created bycurrent flowing through coil I28 of RC is unopposed under this conditionand therefore magnetic fiux will flow through the righthand members ofthe relay structure. It is apparent then that the sequence of operationsfor the circuit of Fig. 11 is the same as that previously examined inreference to Fig. 9.

It is to be understood that the scope of the.

present invention is not limited to the particular arrangementillustrated by the accompanying drawings, but that numerousmodifications may be made, both in the design of the relay structure andin the arrangement of the operating circuit, without departing from thespirit of the present invention as defined by the specification and theappended claims.

What is claimed is:

1. A relay comprising two groups of fixed laminations of magneticmaterial, principal spring tongues of magnetic material attractable intoconductive engagement with fixed laminations in both groups, subordinatespring tongues attractable into conductive engagement with the fixedlaminations of one group, laminations of insulating material interposedbetween said fixed laminations and said spring tongues, energizing coilssurrounding said groups of laminations respectively, and lost motionmechanical coupling means interposed between said principal springtongues and said subordinate spring tongues whereby upon alternateenergization and deenergization of said coils respectively, saidprincipal tongues are sequentially attracted into conductive engagementwith adjacent fixed laminations, and said subordinate tongues aresequentially disengaged from adjacent fixed laminations by saidmechanical coupling means of both groups and said subordinate tonguesare sequentially disengaged from adjacent laminations of one group byoperation of said lost motion coupling means.

2. A relay comprising two stacks of rigid laminations of magneticmaterial, a first set of flexible spring tongues of magnetic materialinterposed between adjacent layers of said rigid laminations andseparated therefrom by laminations of insulating material, a second setof flexible spring tongues each in the plane of one tongue of said firstset, mechanical coupling means interposed between flexible springtongues of said first set whereby said springs are normally restrainedfrom conductive engagement with adjacent rigid laminations of bothstacks, further mechanical means including lost motion links betweentongues of said first and second sets in adjacent layers, energizingcoils surrounding each stack of said rigid laminations whereby uponenergization and deenergization of said coils alternately said first setof springs are sequentially attracted into conductive engagement withadjacent rigid laminations, and said second set of spring aresequentially disengaged by operation of said lost motion links fromcontact with adjacent rigid laminations.

3. In a relay structure two adjacent stacks of fixed laminations ofmagnetic material, laminations of both stacks insulated from each otherand from laminations of said adjacent stack by layers of insulatingmaterial interposed between the laminations of said stacks, a pluralityof primary and secondary spring tongues of magnetic material inadjoining layers interposed between adjacent layers of said insulatingmaterial in proximity to said fixed laminations, mechanical couplingstuds interposed between primary spring tongues in adjoining layerswhereby said primary tongues are normally restrained from conductiveengagement with adjacent fixed laminations of both stacks, furthermechanical studs interposed between primary spring tongues of alternatelayers and secondary spring tongues of an adjoining layer in a manner toinclude an air-gap between said further studs and said spring tongues ofan adjoining layer, magnetic contacts on one side of said primary springtongues adjacent to and in substantial alignment with correspondingmagnetic contacts on facing sides of adjacent fixed laminations in bothgroups, non-magnetic spacers on the opposite side of said primary springtongues from said magnetic contacts, further magnetic contacts on eachof said secondary spring tongues normally in conductive engagement witha like magnetic contact on an adjacent fixed lamination, and energizingcoils surrounding each of said stacks of fixed laminations whereby, uponsequential energization and deenergization of said coils respectively,said primary spring tongues are sequentially attracted into conductiveengagement with adjacent fixed laminations of both groups and saidsecondary spring tongues are successively disengaged from contact withadjacent fixed laminations by said further mechanical studs.

4. An impulse counting system comprising in combination a continuitytransfer relay, a source of electrical energy, and a magnetic contactcounting relay comprising two adjoining stacks of fixed laminations ofmagnetic material, laminations of insulating material interposed betweenadjacent laminations of said magnetic material, a plurality of primaryand secondary armatures of magnetic material interposed between adjacentlayers of said stacked fixed laminations and insulated therefrom, atertiary armature of magnetic material, mechanical coupling meansinterposed between adjacent armatures, energizing coils surrounding eachof said stacks of fixed ilaminations, one of said coils connected tosaid energy source through one contact of said continuity transferrelay, the other of said coils connected to said energy source throughsaid tertiary armature and another contact of said continuity transferrelay whereby upon successive operation of said continuity transferrelay potential is applied from said source of electrical energy toalternately energize and deenergize said coils and successivelyestablish cont-act between said primary armatures and adjacent fixedlaminations.

5. A magnetic contact counting relay comprising a plurality of rigidlaminations of magnetic material arranged in two adjacent stacks,laminations of each stack insulated from the opposite stack, each stackcomprising layers of magnetic members having alternate long and shortpolepieces in alternate layers, the long pole-pieces in alternate layersof each stack abutting opposite short pole-pieces in alternate layers ofthe other stack in a manner to provide substantially uniform air gapsbetween opposing pole-pieces of the two stacks, insulation betweenadjacent lamin-ations, further laminations of magnetic material in theform of flexible spring tongues inter- 19 posed between adjacent layersof said rigid laminations and isolated therefrom bysaid insulation, oneof each such further laminations interleaved between each-two adjacentlayers of said rigid laminations, each, of said further laminationscomprising a main spring tongue, alternate layers of 'said furtherlaminations comprising a narrow auxiliary springtongue in addition tosaid main spring tongue, magnetic contact surfaces on the upper face ofeach of said main spring tongues and non-magnetic spacers on theopposite face of each of said tongues, further magnetic contact.surfaces on. the lower face of each of. said auxiliary spring tongues,magnetic contact, surfaces on the faces of said magnetic polepiecesaligned with and adjacent to said contact surfaces'on. said tongues,said spring tongues being normally biased downwardly into engagementwith the pole-pieces. of the next adjacent layer ofsaid"rigidlaminations, an insulated stud associated with each of said.auxiliary spring tongues and adapted to be engaged by th main tonguelamination of the next adjacent layer below said auxiliary tongue whensaid next ad jacent main spring tongue moves into operated position,further insulated studs associated with said main spring tongues in eachlayer in a manner to bear upon and restrain all main tongues below saidlayer into their norm-ally downward biased positions, and a pair ofoperating coils, one of said coils wound around each of said stacks ofrigid laminations, whereby upon alternate energization anddeenergization of said coils said spring tongues are sequentially movedone at a time into conductive engagement with the next adjacent pair ofmagnetic pole-pieces, and said auxiliary spring tongues are successivelydisengaged one at a time from their conductive cont-acts.

6. A magnetic contact counting relay according to claim comprising anadditional armature operable only upon operation of the lastsequentially operated spring tongues of said relay to open circuits ofboth operating coils and condition said relay for recycling.

7. A magnetic contact counting relay according to claim 5 in combinationwith a continuity transfer relay, a source of electrical potential, andmeans for generating a series of electrical impulses sequentially.

8. A magnetic contact counting relay accord- 'ing to claim 5 incombination with means for generating sequential electrical impulses,and re cycling means comprising an additional auxiliary armature tongueoperable at the end of each counting cycle to restore said countingrelay to normal.

9. In a magnetic contact counting relay according to claim 5 an armaturelamination comprising a plurality of magnetic armatures each bearingmagnetic contacts at their outer extremities.

In a relay structure two groups of fixed laminations of magneticmaterial, a first set of magnetic armatures attractable into conductiveengagement with laminationsof both groups but normally disengagedtherefrom, a second set of magnetic armatures each of which is normallyin conductive engagement with a fixed lamination of one group,energizing coils surrounding each of said groups of laminationsrespectively for attracting successive armatures of said first set intoconductive engagement with adjacent laminations of both groups uponalternate en-- tures of said first set are sequentially attracted intooperative engagement.

11. An impulse counting relay comprising a plurality of layers ofmagnetic laminations in adjacent stacks, each of said laminationsinsulated from the others and each bearing an electrically conductivemagnetic surface on one face thereof, a plurality of layers of magneticspring armatures interposed between layers of said'magnetic laminationsand insulated'therefrom and from.

each other, alternate layers of armatures comprising a main armature andan auxiliary armature, said main armatures having electricallyconductive magnetic surfaces on one face thereof and a non-magnetic.surface on the opposite face thereof, electrically conductive magneticsurfaces on one face of said auxiliary armatures, energizing coilssurrounding each stack of magnetic laminations, mechanical couplingmeans extending between main armatures in adjoining layers, meansincluding said mechanical coupling normally holding the electricallyconductive magnetic surfaces of said main armatures disengaged fromadjacent conductive surfaces of said magnetic laminations, meansnormally holding the electrically conductive surfaces of said auxiliaryarmatures in conductive engagement with corresponding surfaces ofadjacent mag netic laminations, and further mechanical means includinglost motion coupling between said main armatures and auxiliary armaturesin adjoining layers whereby upon alternate energization anddeenergization of said coils said main armatures are sequentiallyattracted into conductive engagement with adjacent magnetic laminationsand said auxiliary armatures are successively disengaged from electricalcontact with said laminations.

THOMAS P. FARKAS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS REFERENCES Application 107,156 filed July 28,1949,Patent 2,564,432, Aug. 14, 1951.

HOW

